Some devices provide a sensory feedback to the human user or operator so that the operator has confidence that the operation sought by the operator has been properly registered. Such is the case, for example, for some computer input devices, such as a mouse or other pointer device which provides a clicking sensation when depressed or operated. By contrast, some input devices, such as a touch screen, for example, do not provide such a click or sensory confirmation. For that reason, it has been proposed to use haptic technology so that, upon human input, a touch screen vibrates in order to provide the confirmatory feedback to the user that the touch screen is receptive to the input. In general, “haptics” is a field of technology which takes advantage of the sense of touch by applying forces, vibrations, or motions to the user Mechanical stimulation provided by haptic devices can be used to assist in the creation of virtual objects in a computer simulation, to control such virtual objects, and to enhance the remote control of machines and devices (telerobotics). Haptic devices may incorporate tactile sensors that measure forces exerted by the user on the interface.
There are many types of haptic electromechanical feedback devices. High definition haptic devices are typically designed to provide a haptic impulse response in less than 20 ms response time, with acceleration response values well exceeding 5-8 Gs.
High definition haptic devices have previously utilized housing structures external from a magnetic circuit to locate components of the magnetic circuit relative to mechanical actuation members, and to allow mounting to other system components. Use of a housing external from the magnetic circuit is also due in part to adverse affects on the magnetic circuit caused by the mounting structure, resulting in degradation in performance. As prior art housing structures require certain size packaging parameters to be used, this establishes size restrictions on where high definition actuation devices can be utilized. In particular, thin panel haptic devices have been unable to package high definition haptic actuators.
In one previous prior art example, an external mounting housing feature was combined to also provide a return spring function. But even in this prior art approach a significant amount of space is consumed. In any case where the frame is fabricated from a plastic material, there can also be inconsistencies in a spring rate of the device, as well as the plastic material having some internal damping while deflecting. These factors combine to produce less than ideal performance results.